this is the only thai veggie dip i know with peanut butter that's not used for satay. however, this one has pork... maybe it's still not what you are looking for. hope someone else can help you further...

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Pork and peanut dip (Moon Lon)
This dip is primarily for Deep-Fried Rice Crackers but is also used with crisp vegetables , raw or lightly cooked.
make about 1 1/2 cup

3/4 cup coconut milk
1 t. pepper and coriander paste (see followed)
4 oz. minced pork
2 T. peanut butter
2 spring onions, finely sliced
2 T. fish sauce
1 t. palm sugar
1 red chilli, finely sliced

heat the coconut milk until bubbling and cook the pepper and coriander paste until fragrant (with low fire). add the minced pork and fry, stirring constantly, until it changes colour. Stir in the peanut butter, spring onions, fish sauce, palm sugar and chilli. Turn heat down and simmer for 10 minutes or until the pork is tender. If necessary, add a little water to the sauce to produce a dipping consistency.

pepper and coriander paste (Rark Pak Chee, Prik Thai)
make about 1 cup

1 T. chopped garlic
2 t. salt
2 T. whole black peppercorns
2 cup well-washed, coarsely chopped fresh coriander, including roots
2 T. lime juice (lemon ok)

crush the garlic with the salt to a smooth paste. roast the peppercorns in a dry pan for a minute or two , then coarsely crush in a mortar and pestle. finely chopped the coriander roots, leaves and stems. Mix all together, adding the lime juice.
This paste may also be made in a blender, but in this case reduce the black peppercorns to 1 T. because it is hotter if finely ground than if coarsely crushed.